CN112142143A - System and method for removing heavy metal and chloride ions in evaporative crystallization process of desulfurization wastewater - Google Patents
System and method for removing heavy metal and chloride ions in evaporative crystallization process of desulfurization wastewater Download PDFInfo
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- CN112142143A CN112142143A CN202011099205.1A CN202011099205A CN112142143A CN 112142143 A CN112142143 A CN 112142143A CN 202011099205 A CN202011099205 A CN 202011099205A CN 112142143 A CN112142143 A CN 112142143A
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- C02F1/00—Treatment of water, waste water, or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/10—Treatment of water, waste water, or sewage by heating by distillation or evaporation by direct contact with a particulate solid or with a fluid, as a heat transfer medium
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Abstract
The invention provides a system and a method for removing heavy metal and chloride ions in an evaporative crystallization process of desulfurization wastewater. Comprises an SCR reactor, an air preheater, a primary heat pipe evaporator, a secondary heat pipe evaporator, a hot air curtain drying tower, a desulfurization waste water liquid storage tank and an indirect evaporative cooler; according to the invention, the desulfurization wastewater is subjected to two-stage evaporation concentration by using the waste heat of the flue gas through the first-stage and second-stage heat pipe evaporators, so that a high-quality steam heat source is saved, the energy is saved, the consumption is reduced, and meanwhile, the components of the flue gas are not changed in the process of cooling and heat exchange of the flue gas; the problem of steam condensation, recovery and cyclic comprehensive utilization is solved through the indirect evaporative cooler, so that zero discharge of waste water is realized, and high-quality steam condensate is obtained without loss; the hot air curtain drying tower ensures that the flow field of the high-temperature flue gas entering the body area of the hot air curtain drying tower is uniform and stable, and eliminates the instability factor of the vortex generated in the flow field.
Description
Technical Field
The invention relates to the technical field of high-salinity wastewater treatment in the treatment process of environmental engineering, in particular to a novel zero-discharge system for efficiently evaporating and synergistically removing heavy metals and chloride ions from high-salinity wastewater by using high-temperature flue gas waste heat and a use method thereof.
Background
At present, the conventional process method for treating coal-fired flue gas desulfurization wastewater at home and abroad is a triple-box technology, namely the desulfurization wastewater is treated by the flow processes of neutralization, sedimentation, flocculation, clarification and the like, although most harmful substances which have great harm to the environment can be removed by the process, chloride ions and heavy metal ions cannot be removed, the wastewater containing the chloride ions and the heavy metal ions is discharged, and the process has great potential harm to the environment.
The existing desulfurization wastewater concentration treatment process mainly adopts three technical routes of membrane concentration, thermal concentration and flue gas concentration. Wherein the membrane concentration mode has easy blockage of the membrane and high replacement and investment cost. The MED and MVR technologies of thermal flash evaporation concentration use steam as a heat source, so the operation cost is extremely high; meanwhile, the MVR technology needs electric drive, steam parameters are improved, power consumption is high, most of mechanical steam compressors are imported products, and investment cost is high. The flue gas concentration technology adopts low-temperature flue gas, so that the evaporation capacity is not too large, the flue gas concentration technology is influenced by the humidity of the flue gas, the flue gas concentration technology is not suitable for treating the working condition of large water quantity, and the comprehensive utilization of the fly ash is influenced to a certain extent.
The volume of the high-salinity wastewater after the concentration treatment of the desulfurization wastewater is greatly reduced, the energy consumption of evaporation drying is greatly reduced, the process of directly evaporating and drying the high-salinity wastewater is gradually popularized at present, the operation is simple, the investment cost is low, the zero discharge of the high-salinity wastewater is realized, the environment is not polluted, and the ash content with certain utilization value can be obtained. The existing common drying and evaporating device is high-speed rotary atomizing and two-fluid spray gun atomizing and evaporating drying device, but the two processes have the defects of easy blockage, high operation failure rate and difficult cleaning, and are difficult to ensure long-term stable operation.
Therefore, the research and development of the system for treating the zero discharge of the waste water, which has the advantages of stable operation, high energy-saving and consumption-reducing performance, low scaling risk, absolute zero discharge of waste water and solid waste, comprehensive cyclic utilization of waste, good environmental protection benefit and economic benefit, and environment-friendly cyclic evaporation of the waste heat of the flue gas and synergistic promotion of the removal of the heavy metal ions and the chloride ions, has important significance.
The technical problem to be solved by the invention is as follows: overcomes the defects of high energy consumption rate, high operating cost, easy structural blockage of a system and the like in the prior desulfurization wastewater concentration technology and evaporation technology. The invention provides the wastewater zero-discharge treatment system and the method which can stably, energy-saving and low-consumption operate, have low scaling and blocking risks and are environment-friendly, and efficiently evaporate the waste heat of the flue gas and synergistically promote the removal of the heavy metal ions and the chloride ions.
Disclosure of Invention
Aiming at the technical problems, the invention provides a system and a method for synergistically promoting the removal of heavy metal and chloride ions, in particular to a system and a method for synergistically promoting the removal of heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater.
In order to achieve the purpose, the invention adopts the following technical scheme: the system comprises an SCR reactor, an air preheater, a primary heat pipe evaporator, a secondary heat pipe evaporator, a hot air curtain drying tower, a desulfurization wastewater liquid storage tank and an indirect evaporative cooler; the SCR reactor is respectively connected with an air preheater, a primary heat pipe evaporator, a secondary heat pipe evaporator and a hot air curtain drying tower through pipelines; the air preheater is respectively connected with the primary heat pipe evaporator, the secondary heat pipe evaporator and the hot air curtain drying tower through pipelines; the first-stage heat pipe evaporator is respectively connected with the second-stage heat pipe evaporator, the hot air curtain drying tower, the desulfurization waste water liquid storage tank and the indirect evaporative cooler through pipelines; the secondary heat pipe evaporator is respectively connected with the hot air curtain drying tower, the desulfurization waste water liquid storage tank and the indirect evaporative cooler through pipelines; the hot air curtain drying tower is connected with the desulfurization wastewater liquid storage tank through a pipeline.
Preferably, the first-stage heat pipe evaporator and the second-stage heat pipe evaporator further comprise a flue gas chamber and a flue gas chamber, an inlet section at the upper part of the flue gas chamber and an inlet section at the upper part of the flue gas chamber, a flue gas fin section and a flue gas fin section, an outlet of the flue gas chamber and an outlet of the flue gas chamber, an evaporation chamber and an evaporation chamber, an inlet section at the upper part of the evaporation chamber and an inlet section at the upper part of the evaporation chamber, a heat pipe fin section and a heat pipe fin section, an outlet section at the lower part of the evaporation chamber and an outlet section at the lower part of the; the flue gas fin section is connected with the heat pipe fin section through a pipeline; the flue gas fin section is connected with the heat pipe fin section through a pipeline.
Preferably, the hot air curtain drying tower further comprises a hot air curtain booster fan, a flue gas regulating valve of the hot air curtain drying tower, a hot air curtain main pipe system, a single-phase flow atomization spray gun and a drying tower body; the hot air curtain drying tower flue gas regulating valve is connected with the drying tower body; the hot air curtain booster fan is connected with the hot air curtain main pipe system; the single-phase flow atomization spray gun is connected with the drying tower body; the hot air curtain main pipe system is divided into three layers; the three-layer hot air curtain main pipe system comprises a first layer hot air curtain main pipe valve, a first layer hot air curtain main pipe, a first layer hot air curtain Venturi injection ring, a second layer hot air curtain main pipe valve, a second layer hot air curtain main pipe, a second layer hot air curtain Venturi injection ring, a third layer hot air curtain main pipe valve, a third layer hot air curtain Venturi injection ring and a fourth layer hot air curtain Venturi injection ring; the three-layer hot air curtain main pipe system is connected through a pipeline.
Preferably, the indirect evaporative cooler comprises a condensing chamber and a cooling chamber; the condensing chamber comprises an inlet, a heat pipe fin section and a lower half part outlet; the cooling chamber comprises a cooling fan, an upper collecting section, an atomization spraying section and a cooling liquid collecting tank.
Preferably, the desulfurization waste water liquid storage tank collects and stores the waste water transported and conveyed by wet flue gas desulfurization, and the desulfurization waste water is pumped to the waste water spraying assembly interface of the evaporation chamber of the first-stage heat pipe evaporator by the desulfurization waste water delivery pump. The 300 ℃ high-temperature flue gas led from the outlet flue of the SCR reactor is connected with the inlet of a primary flue gas regulating valve, the outlet of the primary flue gas regulating valve is connected with the upper inlet section of a flue gas chamber of a primary heat pipe evaporator, the flue gas fully diffuses after entering the flue gas chamber and contacts with a flue gas fin section for heat exchange, a heat transfer medium in a heat pipe is heated, and the medium in the heat pipe is heated and evaporated and then is transported to the heat pipe fin section of the left evaporation chamber; after the desulfurization wastewater is atomized by the wastewater spray assembly, wastewater liquid with the average particle size of 200-.
Preferably, the outlet of the flue gas chamber of the first-stage heat pipe evaporator is connected with a bag-type dust collector; the outlet of the smoke chamber of the second-stage heat pipe evaporator is connected with a bag-type dust collector; the outlet of the evaporation chamber of the second-stage heat pipe evaporator is connected with the second-stage waste liquid tank, waste liquid after the second-stage concentration of the evaporation chamber of the second-stage heat pipe evaporator converges to the second-stage waste liquid tank at the outlet section of the evaporation chamber for storage, the second-stage waste liquid tank is connected with a second-stage waste liquid pump, the second-stage waste liquid is pressurized by the second-stage waste liquid pump and then divided into two paths, one path of waste liquid is connected with a single-phase flow spray gun of the hot air curtain drying tower, and the other path of waste.
Preferably, the heat pipe heat exchange element is provided with two sections of finned tubes along the length direction, wherein the left finned tube is correspondingly arranged in the desulfurization wastewater evaporation chamber, the right finned tube is correspondingly arranged in the flue gas chamber, and the length of the finned tube is 1:1 in the ratio of the desulfurization wastewater evaporation chamber to the flue gas chamber; the heat exchange element of the secondary heat pipe evaporator adopts a heat pipe heat exchange element; the second-stage heat pipe evaporator comprises a first-stage waste liquid evaporation chamber and a smoke gas chamber which are sequentially arranged from left to right, a coupling sealing partition plate is arranged between the smoke gas chamber and the first-stage waste liquid evaporation chamber, the coupling sealing partition plate is rigidly connected with the heat pipe heat exchange element, and the coupling sealing partition plate ensures absolute isolation of the smoke gas chamber and the first-stage waste liquid evaporation chamber; the heat pipe heat exchange element in the secondary heat pipe evaporator is provided with two sections of finned tubes along the length direction, wherein the left finned tube is correspondingly arranged in the primary waste liquid evaporation chamber, the right finned tube is correspondingly arranged in the flue gas chamber, and the length of the finned tubes in the primary waste liquid evaporation chamber and the flue gas chamber is 1:1 in proportion.
Preferably, the inlet of the dry hot air regulating valve is connected with the outlet flue of the SCR reactor; the outlet of the drying hot air regulating valve is connected with the inlet at the top of the hot air curtain drying tower; the inlet of the hot air curtain booster fan is connected with the outlet flue of the SCR reactor; the outlet pipeline of the hot air curtain booster fan is divided into three branches, and each branch pipeline is respectively connected with an annular hot air curtain main pipe; the outlet of the hot air curtain drying tower is connected with the inlet of a drying air bag-type dust collector; the hot air curtain drying tower comprises a strip-shaped air distribution grid at the tower inlet, a hot air curtain annular main pipe, a hot air curtain Venturi injection ring, a single-phase flow high-pressure atomizing spray gun and a vortex static separator; the hot air curtain annular main pipe is connected with an outlet pipeline of a hot air curtain drying fan; the hot air curtain annular main pipe is connected with the inlet chamber of the hot air curtain Venturi injection ring through short pipes, and the communicating short pipes are distributed and distributed along the annular symmetry and are not less than 6 communicating short pipes; the inlet chamber of the venturi injection ring of the hot air curtain is uniformly isolated into independent chambers with corresponding number according to the distribution number of the communicating short pipes; the pressurized hot flue gas is introduced into the single independent cavity and forms a high-speed adherence air curtain through a hot air curtain Venturi injection ring, so that the possibility that atomized fine liquid drops at the central position of the drying tower approach the tower wall is isolated, the liquid drops close to the tower wall are quickly pushed to the central area of the tower under the carrying force of the adherence air curtain and are instantly evaporated by the hot flue gas; the hot air curtain annular main pipe and the hot air curtain Venturi injection ring are arranged in three layers to form the wall-attached air curtain series connection relay of the drying tower and keep the continuous and efficient operation of the wall-attached hot air curtain; the vortex static separator pre-separates salt in the flue gas after complete evaporation and drying under the action of centrifugal force, and the pre-separated flue gas is connected with an inlet of a drying air bag-type dust collector; the nozzle of the single-phase flow atomization spray gun is positioned in the central area of the hot air curtain drying tower, and the elevation of the spray gun is positioned between the Venturi injection rings of the first layer and the second layer of the hot air curtain; the operation flow speed of the flue gas empty tower in the hot air curtain drying tower is 1-2 m/s; the flow velocity of flue gas at the outlet of the venturi injection ring of the hot air curtain is 10-20 m/s; the hot air curtain Venturi injection ring enters the cavity, the top of the cavity is tangent to the tower wall to form a streamline structure, and the tower wall adherence air curtain is thrown to the central smoke area of the drying tower along the streamline at the top of the hot air curtain Venturi injection ring.
Preferably, the heat exchange element of the indirect evaporative cooler is a heat pipe heat exchange element; the indirect evaporative cooler comprises an indirect evaporative cooling chamber and a steam condensing chamber which are sequentially arranged from left to right, a coupling sealing partition plate is arranged between the indirect evaporative cooling chamber and the steam condensing chamber, the coupling sealing partition plate is rigidly connected with the heat pipe heat exchange element, and the coupling sealing partition plate ensures absolute isolation of the indirect evaporative cooling chamber and the steam condensing chamber; the heat pipe heat exchange element in the indirect evaporative cooler is provided with two sections of finned tubes along the length direction, wherein the left finned tube is correspondingly arranged in the indirect evaporative cooling chamber, the right finned tube is correspondingly arranged in the steam condensing chamber, and the length of the finned tubes in the indirect evaporative cooling chamber and the steam condensing chamber is 1: 1; the indirect evaporative cooling chamber top export set up cooling blower, set up to outdoor air inlet between indirect evaporative cooling chamber and the cooling collecting tank, indirect evaporative cooling chamber and cooling blower between set up cooling water atomization spray assembly, cooling water pump with the cooling water pump sending to the cooling water atomization spray assembly of cooling collecting tank.
Preferably, the system for removing heavy metal and chloride ions in the evaporative crystallization process of the desulfurization wastewater further comprises a method;
the method comprises the following steps: sucking 300 ℃ flue gas from an outlet flue of the SCR reactor and introducing the flue gas into a flue gas chamber of a first-stage heat pipe evaporator; the desulfurization wastewater in the desulfurization wastewater liquid storage tank is conveyed to a desulfurization wastewater atomization spraying assembly interface at the upper part of the desulfurization wastewater evaporation chamber through a desulfurization wastewater conveying pump; the heat exchange is carried out through the heat pipe element, after the desulfurization wastewater is evaporated and concentrated, the mass concentration of inorganic salt in the desulfurization wastewater is concentrated to 15-20% from the initial 2-4%, the concentrated desulfurization wastewater is discharged to the primary waste liquid tank from the lower part of the desulfurization wastewater evaporation chamber of the primary heat pipe evaporator, and the steam generated by the desulfurization wastewater through the heat evaporation on the surface of the heat pipe heat exchange element of the desulfurization wastewater evaporation chamber of the primary heat pipe evaporator is discharged to the steam condensation chamber of the indirect evaporative cooler through the primary fan.
Step two: the flue gas with the temperature of 300 ℃ is sucked from an outlet flue of an SCR reactor and is introduced into a flue gas chamber of a secondary heat pipe evaporator, primary wastewater (the mass concentration of inorganic salts is 15-20%) in a primary wastewater liquid storage tank is conveyed to a primary wastewater atomization spraying component interface at the upper part of a waste water evaporation chamber of the secondary heat pipe evaporator by a primary wastewater conveying pump, the primary wastewater passes through an atomization spraying component and is sprayed on the surface of a heat pipe heat exchange fin in the waste water evaporation chamber of the secondary heat pipe evaporator to be evaporated and concentrated, heat is exchanged by a heat pipe element, the concentrated primary wastewater is discharged to a secondary waste liquid tank from the lower part of a desulfurization waste water evaporation chamber of the secondary heat pipe evaporator, steam generated by the heat evaporation of the primary wastewater on the surface of the heat pipe heat exchange element of the desulfurization waste water evaporation chamber of the secondary heat pipe evaporator is discharged to a steam condensation chamber of an indirect, and the secondary waste liquid pump pumps the concentrated secondary waste liquid to a single-phase flow atomization spray gun of the air curtain type drying tower.
Step three: the first-stage fan introduces the desulfurization waste water of the first-stage heat pipe evaporator and the steam generated by the evaporation and concentration of the desulfurization waste water of the second-stage heat pipe evaporator into the indirect evaporation cooler, the collected steam enters a condensation chamber of the indirect evaporator, the steam in the condensation chamber is contacted with heat pipe heat exchange element fins, the steam is condensed into condensed water after heat exchange with the heat pipe heat exchange element fins, the condensed water is collected at the lower part of the condensation chamber and discharged to a condensed water tank, the condensed water collected and stored in the condensed water tank is pressurized to 0.1MPa by a condensed water pump and is sent to flushing nozzle interfaces of the first-stage heat pipe evaporator and the second-stage heat pipe evaporator, one part of the condensed water is sent to the waste water evaporator of the first-stage heat pipe evaporator and the waste water evaporation chamber of the second-stage heat pipe evaporator to flush the heat pipe heat exchange element and the fins, and one part of the condensed, certain water is supplemented to the indirect evaporative cooling chamber, and the rest steam condensate is sent to a cooling water system of the boiler unit for recycling; the heat released by the condensation of the steam is transferred to the fin section of the indirect evaporative cooling chamber on the left side through the heat pipe heat exchange element.
Step four: under the power action of pressure difference between an SCR reactor and a bag-type dust collector, flue gas at 300 ℃ is sucked from an outlet flue of the SCR reactor and introduced into an inlet at the top of a hot air curtain drying tower, the flue gas is rectified by a strip-shaped air distribution grid at the inlet of the top drying tower and then uniformly enters a body area of the drying tower, a secondary waste liquid pump conveys secondary high-salinity waste liquid to a single-phase flow atomizing spray gun, the particle size of waste liquid droplets generated after the liquid droplets are atomized by a nozzle is about 50 mu m, the waste liquid droplets are dispersed in the high-temperature flue gas flow entering the top of the drying tower, meanwhile, the 300 ℃ high-temperature flue gas introduced into a hot air curtain annular main pipe is sucked and pressurized by a hot air curtain booster fan from the outlet flue of the SCR reactor and is uniformly conveyed into an inlet chamber of a hot air curtain Venturi injection ring through a communication short pipe, the hot flue gas entering the independent chamber forms a high-speed wall-attached air curtain through, liquid drops close to the tower wall are quickly pushed to the central area of the tower under the carrying force of the adherence air curtain and are instantly evaporated and dried by hot flue gas, the annular main pipe of the hot air curtain and the Venturi injection of the hot air curtain are annularly arranged in three layers to form the series connection relay of the adherence air curtain of the drying tower, the continuous and efficient operation of the adherence hot air curtain is kept, and the flue gas carrying a large amount of salt dust at the outlet of the drying tower of the hot air curtain enters the bag-type dust collector.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention efficiently utilizes the waste heat of the flue gas to carry out two-stage evaporation concentration on the desulfurization wastewater by arranging the heat pipe evaporator, thereby not only saving high-quality steam heat source and saving energy and reducing consumption, but also not changing any flue gas component in the process of cooling and heat exchange of the flue gas. Through setting up the two-stage heat pipe evaporator, the one-level heat pipe evaporator carries out initial concentrated evaporation to desulfurization waste water, and the second grade heat pipe evaporator carries out reconcentration evaporation to the one-level waste liquid, can adjust required concentration according to the technological requirement is nimble, has not only guaranteed the stability of the second grade waste liquid concentration of second grade heat pipe evaporator export, obtains higher waste liquid concentration simultaneously.
2. The invention solves the problem of steam condensation, recovery and cyclic comprehensive utilization through the arrangement of the indirect evaporative cooler, realizes zero discharge of waste water, obtains high-quality steam condensate without loss, and discharges the heat released by the steam condensate to the atmosphere by carrying outdoor fresh air introduced by the cooling fan. The condensed water collected by the processes of evaporation, condensation and the like respectively acts on the washing of the evaporation chamber of the first-stage heat pipe evaporator, the washing of the evaporation chamber of the second-stage heat pipe evaporator, the water replenishing of the cooling liquid of the indirect evaporative cooler, the washing of the system pipeline and the cyclic utilization in the system, thereby realizing the environment-friendly and environment-friendly solution without a multipurpose water source, waste water discharge and waste water evaporation and recovery of the condensed water.
3. The invention ensures the uniformity and stability of the high-temperature flue gas flow field entering the body area of the hot air curtain drying tower by arranging the strip-shaped air distribution rectifying grid at the inlet of the diffusion section of the hot air curtain drying tower, eliminates the instability factor of vortex generation in the flow field, separates the possibility that fine liquid drops atomized at the center position of the drying tower approach the tower wall by arranging the three layers of hot air curtain annular main pipes and the corresponding hot air curtain Venturi injection rings of the hot air curtain drying tower body, quickly pushes the liquid drops close to the tower wall to the center area of the tower under the carrying force of the adherence air curtain and is immediately evaporated and dried by the hot flue gas, and avoids the scaling and blocking possibility that desulfurization waste liquid atomization possibly generates in the tower during the operation process of the hot air curtain drying tower, the stability and the reliability of the system operation are ensured.
Drawings
FIG. 1 is a schematic diagram of a system for synergistically promoting removal of heavy metals and chloride ions in an evaporative crystallization process of desulfurization wastewater;
FIG. 2 is a schematic view of a strip-shaped air distribution and rectification grid;
FIG. 3 is a schematic view of the arrangement of the annular main pipe of the hot air curtain and the corresponding venturi injection ring of the hot air curtain
FIG. 4 is a schematic cross-sectional view of a venturi injection ring of a hot air curtain;
FIG. 5 is a schematic diagram of a primary heat pipe evaporator;
FIG. 6 is a schematic diagram of a two stage heat pipe evaporator;
fig. 7 is a schematic view of an indirect evaporative cooler.
Wherein, 1, an SCR reactor; 2. an air preheater; 3. a first stage heat pipe evaporator; 4. a secondary heat pipe evaporator; 5. a hot air curtain drying tower; 6. a desulfurization waste water storage tank; 7. a secondary waste liquid tank; 8. a secondary waste liquid pump; 9. a primary waste tank; 10. a primary waste liquid pump; 11. a condensation water tank; 12. a condensate pump; 13. an indirect evaporative cooler; 14. a cooling water pump; 15. a cooling fan; 16. a secondary fan; 17. a primary fan; 18. a desulfurization waste water interface; 19. a condensed water discharge port; 20. a desulfurization waste water pump; 21. a flue gas regulating valve of the primary heat pipe evaporator; 22. a flue gas regulating valve of the secondary heat pipe evaporator; 23. drying the air bag dust collector; 24. a flue gas dust remover; 51. a hot air curtain booster fan; 52. a flue gas regulating valve of the hot air curtain drying tower; 531. a first layer of hot air curtain main pipe valve; 532. a first layer of hot air curtain main pipe; 533. a first layer of hot air curtain Venturi injection ring; 541. a second layer hot air curtain main pipe valve; 542. a second layer of hot air curtain main pipe; 543. the second layer of hot air curtain Venturi injection ring; 551. a third layer of hot air curtain main pipe valve; 552. a third layer of hot air curtain main pipe; 553. the third layer of hot air curtain Venturi injection ring; 56. a single-phase flow atomizing spray gun; 57. and drying the tower body.
Detailed Description
In order to further understand the objects, structures, features and functions of the present invention, the following embodiments are described in detail.
Referring to fig. 1 and fig. 2, the present invention provides a system for removing heavy metals and chloride ions in a desulfurization wastewater evaporative crystallization process, wherein the system comprises an SCR reactor 1, an air preheater 2, a primary heat pipe evaporator 3, a secondary heat pipe evaporator 4, a hot air curtain drying tower 5, a desulfurization wastewater liquid storage tank 6 and an indirect evaporative cooler 13; the SCR reactor 1 is respectively connected with an air preheater 2, a primary heat pipe evaporator 3, a secondary heat pipe evaporator 4 and a hot air curtain drying tower 5 through pipelines; the air preheater 2 is respectively connected with the primary heat pipe evaporator 3, the secondary heat pipe evaporator 4 and the hot air curtain drying tower 5 through pipelines; the primary heat pipe evaporator 3 is respectively connected with the secondary heat pipe evaporator 4, the hot air curtain drying tower 5, the desulfurization waste water liquid storage tank 6 and the indirect evaporative cooler 13 through pipelines; the secondary heat pipe evaporator 4 is respectively connected with a hot air curtain drying tower 5, a desulfurization waste water liquid storage tank 6 and an indirect evaporative cooler 13 through pipelines; the hot air curtain drying tower 5 is connected with a desulfurization wastewater liquid storage tank 6 through a pipeline.
Preferably, the primary heat pipe evaporator 3 comprises a flue gas chamber 31, a flue gas chamber upper inlet section 311, a flue gas fin section 312, a flue gas chamber outlet 313, an evaporation chamber 32, an evaporation chamber upper inlet section 321, a heat pipe fin section 322, an evaporation chamber lower outlet section 323 and a waste water spraying assembly 324; the flue gas fin section 312 is connected with the heat pipe fin section 322 through a pipeline.
The secondary heat pipe evaporator 4 comprises a flue gas chamber 41, a flue gas chamber upper inlet section 411, a flue gas fin section 412, a flue gas chamber outlet 413, an evaporation chamber 42, an evaporation chamber upper inlet section 421, a heat pipe fin section 422, an evaporation chamber lower outlet section 423 and a waste water spraying assembly 424; the flue gas fin section 412 is connected with the heat pipe fin section 422 through a pipeline.
Preferably, the hot air curtain drying tower 5 further comprises a hot air curtain booster fan 51, a hot air curtain drying tower flue gas regulating valve 52, a hot air curtain main pipe system, a single-phase flow atomizing spray gun 56 and a drying tower body 57; the hot air curtain drying tower flue gas regulating valve 52 is connected with the drying tower body 57; the hot air curtain booster fan 51 is connected with the hot air curtain main pipe system; the single-phase flow atomization spray gun 56 is fixed on the right side of the drying tower body 57; the hot air curtain main pipe system is divided into three layers; the hot air curtain main pipe system comprises a first layer hot air curtain main pipe valve 531, a first layer hot air curtain main pipe 532, a first layer hot air curtain venturi injection ring 533, a second layer hot air curtain main pipe valve 541, a second layer hot air curtain main pipe 542, a second layer hot air curtain venturi injection ring 543, a third layer hot air curtain main pipe valve 551, a third layer hot air curtain main pipe 552 and a third layer hot air curtain venturi injection ring 553; the three-layer hot air curtain main pipe system is connected through a pipeline.
Preferably, the indirect evaporative cooler 13 includes a condensing chamber 131 and a cooling chamber 132; the condensation chamber 131 comprises an inlet 131-1, a heat pipe fin section 131-2 and a lower half outlet 131-3; the cooling chamber 132 includes a cooling fan 132-2, an upper collection section 132-3, an atomizing spray section 132-4, and a cooling liquid sump 132-6.
Preferably, the desulfurization waste water storage tank 6 collects and stores the waste water transferred and conveyed by wet flue gas desulfurization, and the desulfurization waste water is pumped to the interface of the waste water spraying component 324 of the evaporation chamber 32 of the first-stage heat pipe evaporator 3 by the desulfurization waste water conveying pump 20. The 300 ℃ high-temperature flue gas led from the outlet flue of the SCR reactor 1 is connected with the inlet of a first-stage flue gas regulating valve 21, the outlet of the first-stage flue gas regulating valve 21 is connected with the upper inlet section 311 of a flue gas chamber 31 of a first-stage heat pipe evaporator 3, the flue gas enters the flue gas chamber 31 and is fully diffused to contact with a flue gas fin section 312 for heat exchange, a heat transfer medium in a heat pipe is heated, and the medium in the heat pipe is heated and evaporated and then is transported to a heat pipe fin section 322 of an evaporation chamber on the left side; the desulfurization wastewater is atomized by the wastewater spray assembly 324 to form wastewater liquid with the average particle size of 200-.
Preferably, the outlet 313 of the flue gas chamber of the first-stage heat pipe evaporator 3 is connected with the bag-type dust collector 23; the outlet 413 of the smoke chamber of the second-stage heat pipe evaporator 4 is connected with the bag-type dust collector 3; the outlet 423 of the evaporation chamber of the second-stage heat pipe evaporator is connected with the second-stage waste liquid tank, the waste liquid after the second-stage concentration of the evaporation chamber 42 of the second-stage heat pipe evaporator 4 converges to the second-stage waste liquid tank 7 at the outlet 423 of the evaporation chamber 42 for storage, the second-stage waste liquid tank 7 is connected with the second-stage waste liquid pump 8, the second-stage waste liquid is pressurized by the second-stage waste liquid pump and then divided into two paths, one path is connected with the single-phase flow spray gun 56 of the hot air curtain drying tower 5, and the other path is connected with the desulfurization waste.
Preferably, the inlet of the flue gas regulating valve 52 of the hot air curtain drying tower is connected with the outlet flue of the SCR reactor; the outlet of the flue gas regulating valve 52 of the hot air curtain drying tower is connected with the inlet at the top of the hot air curtain drying tower 5; an inlet of the hot air curtain booster fan 51 is connected with an outlet flue of the SCR reactor; the outlet pipeline of the hot air curtain booster fan 51 is divided into three branches, and each branch pipeline is respectively connected with an annular hot air curtain main pipe; the outlet of the hot air curtain drying tower 5 is connected with the inlet of a drying air bag-type dust collector 23; the hot air curtain drying tower 5 comprises a strip-shaped air distribution grid at the tower inlet, a hot air curtain annular main pipe, a hot air curtain Venturi injection ring, a single-phase flow high-pressure atomizing spray gun and a vortex static separator; the hot air curtain annular main pipe is connected with an outlet pipeline of a hot air curtain drying fan; the hot air curtain annular main pipe is connected with the inlet chamber of the hot air curtain Venturi injection ring through short pipes, and the communicating short pipes are distributed and distributed along the annular symmetry and are not less than 6 communicating short pipes; the inlet chamber of the venturi injection ring of the hot air curtain is uniformly isolated into independent chambers with corresponding number according to the distribution number of the communicating short pipes; the pressurized hot flue gas is introduced into the single independent cavity and forms a high-speed adherence air curtain through a hot air curtain Venturi injection ring, so that the possibility that atomized fine liquid drops at the central position of the drying tower approach the tower wall is isolated, the liquid drops close to the tower wall are quickly pushed to the central area of the tower under the carrying force of the adherence air curtain and are instantly evaporated by the hot flue gas; the hot air curtain annular main pipe and the hot air curtain Venturi injection ring are arranged in three layers to form the wall-attached air curtain series connection relay of the drying tower and keep the continuous and efficient operation of the wall-attached hot air curtain; the vortex static separator pre-separates salt in the flue gas after complete evaporation and drying under the action of centrifugal force, and the pre-separated flue gas is connected with an inlet of a drying air bag-type dust collector; the nozzle of the single-phase flow atomization spray gun is positioned in the central area of the hot air curtain drying tower, and the elevation of the spray gun is positioned between the Venturi injection rings of the first layer and the second layer of the hot air curtain; the operation flow speed of the flue gas empty tower in the hot air curtain drying tower is 1-2 m/s; the flow velocity of flue gas at the outlet of the venturi injection ring of the hot air curtain is 10-20 m/s; the hot air curtain Venturi injection ring enters the cavity, the top of the cavity is tangent to the tower wall to form a streamline structure, and the tower wall adherence air curtain is thrown to the central smoke area of the drying tower along the streamline at the top of the hot air curtain Venturi injection ring.
Preferably, the heat exchange element of the indirect evaporative cooler 13 is a heat pipe heat exchange element; the indirect evaporative cooler 13 comprises an indirect evaporative cooling chamber 131 and a steam condensing chamber 132 which are sequentially arranged from left to right, a coupling sealing partition plate is arranged between the indirect evaporative cooling chamber and the steam condensing chamber, the coupling sealing partition plate is rigidly connected with a heat pipe heat exchange element, and the coupling sealing partition plate ensures that the indirect evaporative cooling chamber 131 and the steam condensing chamber 132 are absolutely isolated; the heat pipe heat exchange element in the indirect evaporative cooler 13 is provided with two sections of finned tubes along the length direction, wherein the left finned tube is correspondingly arranged in the indirect evaporative cooling chamber 131, the right finned tube is correspondingly arranged in the steam condensing chamber 132, and the length of the finned tubes in the indirect evaporative cooling chamber 131 and the steam condensing chamber 132 is 1: 1; the cooling water atomization spraying component is arranged between the indirect evaporative cooling chamber 13 and the cooling fan, and the cooling water pump 14 sends the cooling water of the cooling liquid collecting tank to the cooling water atomization spraying component 132-4.
Preferably, the system for removing heavy metals and chloride ions in the evaporative crystallization process of the desulfurization wastewater further comprises a using method, and comprises the following steps:
the method comprises the following steps: under the power action of the pressure difference between the SCR reactor 1 and the bag-type dust collector 23, 300 ℃ flue gas is sucked from an outlet flue of the SCR reactor 1 and is introduced into a first-stage heat pipe evaporator 3 to release part of heat for heating and evaporating desulfurization waste water, specifically, 300 ℃ flue gas is sucked from the outlet flue of the SCR reactor 1 and is introduced into a first-stage heat pipe evaporator flue gas chamber 32, desulfurization waste water (inorganic salt mass concentration is 2-4%) in a desulfurization waste water storage tank 6 is conveyed to a desulfurization waste water atomization spraying component 324 interface at the upper part of the desulfurization waste water evaporation chamber 32 through a desulfurization waste water conveying pump 20, the desulfurization waste water is sprayed on the surface of a heat pipe heat exchange fin in the desulfurization waste water evaporation chamber through the desulfurization waste water atomization spraying component 324 to be heated, evaporated and concentrated, heat is exchanged through a heat pipe element, the temperature of the flue gas at the outlet of the first-stage heat pipe evaporator flue gas, the mass concentration of inorganic salts in the desulfurization wastewater is concentrated from 2-4% to 15-20%, the concentrated desulfurization wastewater is discharged from the lower part of the desulfurization wastewater evaporation chamber of the primary heat pipe evaporator 3 to the primary waste liquid tank 9, and steam generated by heating and evaporating the desulfurization wastewater on the surface of a heat pipe heat exchange element of the desulfurization wastewater evaporation chamber of the primary heat pipe evaporator 3 is discharged to a steam condensation chamber 131 of the indirect evaporative cooler 13 through a primary fan 17.
Step two: under the power action of the pressure difference between the SCR reactor 1 and the bag-type dust collector 23, 300 ℃ flue gas is sucked from an outlet flue of the SCR reactor 1 and is introduced into a secondary heat pipe evaporator 4 to release part of heat for heating and evaporating primary wastewater (the concentration of inorganic salt components is 15-20%), specifically, 300 ℃ flue gas is sucked from the outlet flue of the SCR reactor 1 and is introduced into a flue gas chamber 41 of the secondary heat pipe evaporator, the primary wastewater (the concentration of inorganic salt components is 15-20%) in a primary wastewater liquid storage tank 9 is conveyed to a primary wastewater atomization spraying assembly 424 interface at the upper part of a waste water evaporation chamber 42 of the secondary heat pipe evaporator through a primary wastewater conveying pump 10, the primary wastewater is sprayed on the surfaces of heat pipe heat exchange fins in the waste water evaporation chamber 42 of the secondary heat pipe evaporator through the atomization spraying assembly 424 to be heated, evaporated and concentrated, heat is exchanged through a heat pipe element, the temperature of the flue gas at the outlet of the flue gas chamber 41, after the primary wastewater is evaporated and concentrated, the inorganic salt mass concentration of the wastewater is concentrated to 35-45% from the initial 15-20%, the concentrated primary wastewater is discharged to a secondary waste liquid tank 7 from the lower part of a desulfurization wastewater evaporation chamber 42 of a secondary heat pipe evaporator 4, steam generated by the thermal evaporation of the primary wastewater on the surface of a heat pipe heat exchange element of the desulfurization wastewater evaporation chamber 42 of the secondary heat pipe evaporator 4 is discharged to a steam condensation chamber 131 of an indirect evaporative cooler 13 through a secondary fan 16, an inlet of a secondary waste liquid pump 8 is connected with the secondary waste liquid tank 7, and the concentrated secondary waste liquid is pumped to a single-phase flow atomization spray gun 56 of an air curtain type drying tower by the secondary waste liquid pump 8.
The function is as follows: through setting up the heat pipe evaporimeter, the waste heat of high-efficient utilization flue gas carries out the two-stage evaporation concentration to desulfurization waste water, not only can practice thrift the steam heat source of high-quality, energy saving and consumption reduction, does not change any flue gas composition simultaneously in the flue gas cooling heat transfer process. Through setting up the two-stage heat pipe evaporator, the one-level heat pipe evaporator carries out initial concentrated evaporation to desulfurization waste water, and the second grade heat pipe evaporator carries out reconcentration evaporation to the one-level waste liquid, can adjust required concentration according to the technological requirement is nimble, has not only guaranteed the stability of the second grade waste liquid concentration of second grade heat pipe evaporator export, obtains higher waste liquid concentration simultaneously.
Step three: meanwhile, a primary fan 17 introduces steam generated by evaporative concentration of desulfurization wastewater of a primary heat pipe evaporator 3 into an indirect evaporative cooler 13, a secondary fan 16 introduces steam generated by evaporative concentration of desulfurization wastewater of a secondary heat pipe evaporator 4 into the indirect evaporative cooler 13, the collected steam enters a condensing chamber 131 of the indirect evaporator, the steam in the condensing chamber 131 is contacted with heat pipe heat exchange element fins, the steam exchanges heat with the heat pipe heat exchange element fins and is condensed to generate condensed water, the condensed water is collected at the lower part of the condensing chamber 131 and is discharged to a condensed water tank, the condensed water collected and stored in the condensed water tank is pressurized to 0.1MPa by a condensed water pump and is sent to flushing nozzle interfaces of the primary heat pipe evaporator 3 and the secondary heat pipe evaporator 4, one part of the condensed water is sent to a wastewater evaporator 32 of the primary heat pipe evaporator 3 and a wastewater evaporation chamber 42 of the secondary heat pipe evaporator 4 to flush the heat pipe heat exchange elements and fins, one part of the water is sent to a cooling liquid collecting tank of the indirect evaporative cooling chamber 132 of the indirect evaporative cooler 13, certain water supplement is carried out on the indirect evaporative cooling chamber 132, and the rest steam condensate is sent to a cooling water system of the boiler unit for recycling; the heat released by steam condensation is transferred to the fin segment of the indirect evaporative cooling chamber on the left side through the heat pipe heat exchange element, specifically, the cooling water pump 14 pumps the water in the cooling liquid storage tank to an atomizing spray component 132-4 interface on the upper part of the indirect evaporative cooling chamber, the cooling water is atomized and sprayed on the surface of the fin of the heat pipe heat exchange element of the indirect evaporative cooling chamber, under the action of suction force of the cooling fan 15, outdoor air is introduced from an air inlet on the lower part of the indirect evaporative cooling chamber 132, and the flowing outdoor air carries the water vapor evaporated by heating on the surface of the fin of the heat pipe heat exchange element of the indirect evaporative cooling chamber.
The function is as follows: through the setting of indirect evaporative cooler, solved the problem that the circulation was used multipurposely in the steam condensation recovery, not only realized the waste water zero release, still lossless obtains the steam condensate of high quality, and the heat of steam condensate release carries through the outdoor new trend that cooling blower introduced and discharges to the atmosphere. The condensed water collected by the processes of evaporation, condensation and the like respectively acts on the washing of the evaporation chamber of the first-stage heat pipe evaporator, the washing of the evaporation chamber of the second-stage heat pipe evaporator, the water replenishing of the cooling liquid of the indirect evaporative cooler, the washing of the system pipeline and the cyclic utilization in the system, thereby realizing the environment-friendly and environment-friendly solution without a multipurpose water source, waste water discharge and waste water evaporation and recovery of the condensed water.
Step four: under the power action of the pressure difference between the SCR reactor 1 and the bag-type dust collector 23, the flue gas with the temperature of 300 ℃ is sucked from an outlet flue of the SCR reactor 1 and is introduced into an inlet at the top of a hot air curtain drying tower 5, the flue gas is rectified by a strip-shaped air grid at the inlet of the top drying tower 5 and then uniformly enters a body area of the drying tower, the high-salinity secondary waste liquid which is conveyed to a single-phase flow atomizing spray gun 56 by a secondary waste liquid pump 8 has the particle size of about 50 mu m and is dispersed in the high-temperature flue gas flow entering from the top of the drying tower, meanwhile, the high-temperature flue gas with the temperature of 300 ℃ which is introduced into a hot air curtain annular main pipe is sucked and pressurized by a hot air curtain booster fan from the outlet flue of the SCR reactor and is uniformly sent into an inlet chamber of a hot air curtain Venturi injection ring through a communicating short pipe, the hot flue gas which enters an independent chamber forms a high-speed wall-attached air curtain through the, liquid drops close to the tower wall are quickly pushed to the central area of the tower under the carrying force of the adherence air curtain and are instantly evaporated and dried by hot flue gas, the annular main pipe of the hot air curtain and the Venturi injection of the hot air curtain are annularly arranged in three layers to form the series connection relay of the adherence air curtain of the drying tower, the continuous and efficient operation of the adherence hot air curtain is kept, and the flue gas carrying a large amount of salt dust at the outlet of the drying tower of the hot air curtain enters the bag-type dust collector.
The function is as follows: the strip-shaped air distribution rectifying grating is arranged at the inlet position of the diffusion section of the hot air curtain drying tower, so that the uniformity and stability of a high-temperature flue gas flow field entering a hot air curtain drying tower body area are ensured, the instability factor of vortex generation in the flow field is eliminated, the possibility that fine liquid drops atomized at the central position of the drying tower are close to the tower wall is isolated by three layers of hot air curtain annular main pipes and corresponding hot air curtain Venturi injection rings arranged on the hot air curtain drying tower body, the boosted high-temperature flue gas passes through the accelerated injection action of the hot air curtain Venturi injection rings, high-speed wall-attached air curtains are formed at the periphery of the inner wall of the drying tower, the liquid drops close to the tower wall are quickly pushed to the tower central area under the carrying force of the wall-attached air curtains, and are evaporated and dried by hot flue gas immediately, and the scaling and blocking possibility that desulfurization waste liquid atomization possibly generates in the tower, the stability and the reliability of the system operation are ensured.
The present invention has been described in relation to the above embodiments, which are only exemplary of the implementation of the present invention. It should be noted that the disclosed embodiments do not limit the scope of the invention. Rather, it is intended that all such modifications and variations be included within the spirit and scope of this invention.
Claims (10)
1. Heavy metal and chloride ion desorption system among desulfurization waste water evaporative crystallization process, its characterized in that: the system comprises an SCR reactor (1), an air preheater (2), a primary heat pipe evaporator (3), a secondary heat pipe evaporator (4), a hot air curtain drying tower (5), a desulfurization waste water liquid storage tank (6) and an indirect evaporative cooler (13); the SCR reactor (1) is respectively connected with an air preheater (2), a primary heat pipe evaporator (3), a secondary heat pipe evaporator (4) and a hot air curtain drying tower (5) through pipelines; the air preheater (2) is respectively connected with the primary heat pipe evaporator (3), the secondary heat pipe evaporator (4) and the hot air curtain drying tower (5) through pipelines; the primary heat pipe evaporator (3) is respectively connected with the secondary heat pipe evaporator (4), the hot air curtain drying tower (5), the desulfurization waste water liquid storage tank (6) and the indirect evaporative cooler (13) through pipelines; the secondary heat pipe evaporator (4) is respectively connected with the hot air curtain drying tower (5), the desulfurization waste water liquid storage tank (6) and the indirect evaporative cooler (13) through pipelines; the hot air curtain drying tower (5) is connected with the desulfurization wastewater storage tank (6) through a pipeline.
2. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 1, wherein: the primary heat pipe evaporator (3) comprises a flue gas chamber (31), a flue gas chamber upper inlet section (311), a flue gas fin section (312), a flue gas chamber outlet (313), an evaporation chamber (32), an evaporation chamber upper inlet section (321), a heat pipe fin section (322), an evaporation chamber lower outlet section (323) and a waste water spraying assembly (324); the flue gas fin sections (312) are connected with the heat pipe fin sections (322) through pipelines.
3. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 1, wherein: the secondary heat pipe evaporator (4) comprises a smoke gas chamber (41), an inlet section (411) at the upper part of the smoke gas chamber, smoke gas fin sections (412), an outlet (413) of the smoke gas chamber, an evaporation chamber (42), an inlet section (421) at the upper part of the evaporation chamber, heat pipe fin sections (422), an outlet section (423) at the lower part of the evaporation chamber and a waste water spraying assembly (424), wherein the smoke gas fin sections (412) are connected with the heat pipe fin sections (422) through pipelines.
4. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 1, wherein: the hot air curtain drying tower (5) further comprises a hot air curtain booster fan (51), a hot air curtain drying tower flue gas regulating valve (52), a hot air curtain main pipe system, a single-phase flow atomization spray gun (56) and a drying tower body (57); the hot air curtain drying tower flue gas regulating valve (52) is fixed on the right side of the drying tower body (57); the hot air curtain booster fan (51) is connected with the hot air curtain main pipe system; the single-phase flow atomization spray gun (56) is connected with the drying tower body (57); the hot air curtain main pipe system is divided into three layers; the three-layer hot air curtain main pipe system comprises a first layer hot air curtain main pipe valve (531), a first layer hot air curtain main pipe (532), a first layer hot air curtain Venturi injection ring (533), a second layer hot air curtain main pipe valve (541), a second layer hot air curtain main pipe (542), a second layer hot air curtain Venturi injection ring (543), a three-layer hot air curtain main pipe valve (551), a third layer hot air curtain main pipe (552) and a third layer hot air curtain Venturi injection ring (553); the three-layer hot air curtain main pipe system is connected through a pipeline.
5. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 1, wherein: the indirect evaporative cooler (13) comprises a condensing chamber (131) and a cooling chamber (132); the condensing chamber (131) comprises an inlet (131-1), a heat pipe fin section (131-2) and a lower half outlet (131-3); the cooling chamber (132) comprises a cooling fan (132-2), an upper collecting section (132-3), an atomizing spray section (132-4) and a cooling liquid collecting tank (132-6).
6. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 1, wherein: the desulfurization waste water liquid storage tank (6) collects and stores waste water transported and conveyed by wet flue gas desulfurization, and the desulfurization waste water is pumped to a waste water spraying component (324) interface of an evaporation chamber (32) of the first-stage heat pipe evaporator (3) by a desulfurization waste water delivery pump (20).
7. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 2, wherein: a flue gas chamber outlet (313) of the primary heat pipe evaporator (3) is connected with a flue gas dust remover (24); a flue gas chamber outlet (413) of the secondary heat pipe evaporator (4) is connected with a flue gas dust remover (24); the evaporation chamber outlet (423) of the second-stage heat pipe evaporator is connected with the second-stage waste liquid tank, the waste liquid after the second-stage concentration of the evaporation chamber (42) of the second-stage heat pipe evaporator (4) converges to the second-stage waste liquid tank (7) at the outlet section (423) of the evaporation chamber (42) and is stored, the second-stage waste liquid tank (7) is connected with the second-stage waste liquid pump (8), the second-stage waste liquid is pressurized by the second-stage waste liquid pump and then divided into two paths, one path is connected with the single-phase flow spray gun (56) of the hot air curtain drying tower (5), and the other path is connected with the desulfurization waste water storage tank (.
8. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 3, wherein: the inlet of the hot air curtain drying tower flue gas regulating valve (52) is connected with the outlet flue of the SCR reactor (1); the outlet of the flue gas regulating valve (52) of the hot air curtain drying tower is connected with the inlet at the top of the hot air curtain drying tower (5); an inlet of the hot air curtain booster fan (51) is connected with an outlet flue of the SCR reactor (1); the outlet pipeline of the hot air curtain booster fan (51) is divided into three branches, and each branch pipeline is respectively connected with an annular hot air curtain main pipe; the outlet of the hot air curtain drying tower (5) is connected with the inlet of a drying air bag-type dust collector; the hot air curtain annular main pipe is connected with an outlet pipeline of a hot air curtain drying fan; the hot air curtain annular main pipe is connected with the inlet chamber of the hot air curtain Venturi injection ring through short pipes, and the communicating short pipes are distributed and distributed along the annular symmetry and are not less than 6 communicating short pipes; the inlet chamber of the venturi injection ring of the hot air curtain is uniformly isolated into independent chambers with corresponding number according to the distribution number of the communicating short pipes; the pressurized hot flue gas is introduced into the single independent cavity and forms a high-speed adherence air curtain through a hot air curtain Venturi injection ring, so that the possibility that atomized fine liquid drops at the central position of the drying tower approach the tower wall is isolated, the liquid drops close to the tower wall are quickly pushed to the central area of the tower under the carrying force of the adherence air curtain and are instantly evaporated by the hot flue gas; the hot air curtain annular main pipe and the hot air curtain Venturi injection ring are arranged in three layers to form the wall-attached air curtain series connection relay of the drying tower and keep the continuous and efficient operation of the wall-attached hot air curtain; the vortex static separator pre-separates salt in the flue gas after complete evaporation and drying under the action of centrifugal force, and the pre-separated flue gas is connected with an inlet of a drying air bag-type dust collector; the nozzle of the single-phase flow atomization spray gun is positioned in the central area of the hot air curtain drying tower, and the elevation of the spray gun is positioned between the Venturi injection rings of the first layer and the second layer of the hot air curtain; the operation flow speed of the flue gas empty tower in the hot air curtain drying tower is 1-2 m/s; the flow velocity of flue gas at the outlet of the venturi injection ring of the hot air curtain is 10-20 m/s; the hot air curtain Venturi injection ring enters the cavity, the top of the cavity is tangent to the tower wall to form a streamline structure, and the tower wall adherence air curtain is thrown to the central smoke area of the drying tower along the streamline at the top of the hot air curtain Venturi injection ring.
9. The system for removing heavy metal and chloride ions in the evaporative crystallization process of desulfurization wastewater as set forth in claim 4, wherein: the heat exchange element of the indirect evaporative cooler (13) adopts a heat pipe heat exchange element; the indirect evaporative cooler (13) comprises an indirect evaporative cooling chamber (131) and a steam condensing chamber (132) which are sequentially arranged from left to right, a coupling sealing partition plate is arranged between the indirect evaporative cooling chamber (131) and the steam condensing chamber (132), the coupling sealing partition plate is rigidly connected with a heat pipe heat exchange element, and the coupling sealing partition plate ensures that the indirect evaporative cooling chamber (131) and the steam condensing chamber (132) are absolutely isolated; the heat pipe heat exchange element in the indirect evaporative cooler (13) is provided with two sections of finned tubes along the length direction, wherein the left finned tube is correspondingly arranged in the indirect evaporative cooling chamber (131), the right finned tube is correspondingly arranged in the steam condensation chamber (132), and the length of the finned tubes in the indirect evaporative cooling chamber (131) and the steam condensation chamber (132) is 1: 1; the indirect evaporative cooling chamber (13) top export set up cooling blower (15), set up to outdoor air inlet between indirect evaporative cooling chamber (13) and the cooling collecting tank, indirect evaporative cooling chamber (13) and cooling blower (15) between set up the cooling water atomizing and spray (132-4) subassembly, cooling water pump (14) with the cooling water pump sending of cooling collecting tank to the cooling water atomizing and spray subassembly.
10. The system for removing heavy metal and chloride ions in the evaporative crystallization process of the desulfurization wastewater also comprises a using method;
the method comprises the following steps: flue gas with the temperature of 300 ℃ is sucked from an outlet flue of the SCR reactor (1) and is introduced into a flue gas chamber (31) of a first-stage heat pipe evaporator; the desulfurization waste water in the desulfurization waste water storage tank (6) is conveyed to a desulfurization waste water atomization spraying assembly (324) interface at the upper part of a desulfurization waste water evaporation chamber (32) through a desulfurization waste water conveying pump (20); heat exchange is carried out through a heat pipe element, after desulfurization wastewater is evaporated and concentrated, the mass concentration of inorganic salt in the desulfurization wastewater is concentrated to 15-20% from the initial 2-4%, the concentrated desulfurization wastewater is discharged to a primary waste liquid tank (9) from the lower part of a desulfurization wastewater evaporation chamber of a primary heat pipe evaporator (3), and steam generated by heating and evaporating the desulfurization wastewater on the surface of the heat pipe heat exchange element of the desulfurization wastewater evaporation chamber of the primary heat pipe evaporator (3) is discharged to a steam condensation chamber (131) of an indirect evaporative cooler (13) through a primary fan (17);
step two: flue gas with the temperature of 300 ℃ is sucked from a flue of an outlet (1) of an SCR reactor and is introduced into a flue gas chamber (41) of a secondary heat pipe evaporator, primary wastewater (inorganic salt mass concentration is 15-20%) in a primary wastewater liquid storage tank (9) is conveyed to a port of a primary wastewater atomization spraying assembly (424) at the upper part of a wastewater evaporation chamber (42) of the secondary heat pipe evaporator by a primary wastewater conveying pump (10), the primary wastewater is sprayed on the surface of a heat pipe heat exchange fin in the wastewater evaporation chamber (42) of the secondary heat pipe evaporator (4) through the atomization spraying assembly to be evaporated and concentrated, heat exchange is carried out through a heat pipe element, the concentrated primary wastewater is discharged to a secondary waste liquid tank (7) from the lower part of the desulfurization wastewater evaporation chamber of the secondary heat pipe evaporator, steam generated by the heat pipe heat exchange element of the desulfurization wastewater evaporation chamber of the secondary heat pipe evaporator is discharged to a steam condensation chamber (131) of an indirect evaporative cooler (13) through a secondary fan (16, an inlet of a secondary waste liquid pump (8) is connected with a secondary waste liquid tank, and the secondary waste liquid pump pumps the concentrated secondary waste liquid to a single-phase flow atomization spray gun (56) of the air curtain type drying tower;
step three: the method comprises the following steps that a primary fan (17) introduces desulfurization wastewater of a primary heat pipe evaporator (3) and a secondary fan (16) introduces steam generated by evaporation and concentration of desulfurization wastewater of a secondary heat pipe evaporator (4) into an indirect evaporation cooler (13), the collected steam enters a condensation chamber (131) of the indirect evaporator (13), the steam in the condensation chamber (131) is in contact with heat pipe heat exchange element fins, the steam is condensed into condensed water after being subjected to heat exchange with the heat pipe heat exchange element fins, the condensed water is collected at the lower part of the condensation chamber and discharged to a condensed water tank, the condensed water collected and stored in the condensed water tank is pressurized to 0.1MPa through a condensed water pump (12) and is sent to flushing nozzle interfaces of the primary heat pipe evaporator (3) and the secondary heat pipe evaporator (4), one part of the condensed water is sent to a wastewater evaporation chamber (32) of the primary heat pipe evaporator and a wastewater evaporation chamber (42) of the secondary heat pipe evaporator to flush the heat pipe heat exchange elements, one part of the steam is sent to a cooling liquid collecting tank of an indirect evaporative cooling chamber of an indirect evaporative cooler, certain water replenishing is carried out on the indirect evaporative cooling chamber, and the rest steam condensate is sent to a cooling water system of a boiler unit for recycling; the heat released by the condensation of the steam is transferred to the fin section of the indirect evaporative cooling chamber on the left side through the heat pipe heat exchange element;
step four: under the power action of pressure difference between an SCR reactor (1) and a bag-type dust collector (23), smoke with the temperature of 300 ℃ is sucked from an outlet flue of the SCR reactor (1) and is introduced into an inlet at the top (5) of a hot air curtain drying tower, the smoke is rectified by a strip-shaped air distribution grid at an inlet of the top drying tower and then uniformly enters a drying tower body (57) area, a secondary waste liquid pump (8) is used for conveying high-salt secondary waste liquid with the particle size of about 50 mu m to a single-phase flow atomizing spray gun (56), waste liquid droplets generated after atomization by a nozzle are dispersed in high-temperature smoke flow entering from the top of the drying tower (5), meanwhile, the high-temperature smoke with the temperature of 300 ℃ introduced into a hot air curtain annular main pipe is sucked and pressurized from the outlet flue of the SCR reactor (1) by a hot air curtain booster fan (51), and is uniformly conveyed into an inlet chamber of a hot air curtain venturi injection ring by a communication short pipe, the hot smoke entering the independent chamber forms a high-, the probability that atomized fine liquid drops at the center of the drying tower are close to the tower wall is isolated, the liquid drops close to the tower wall are quickly pushed to the center area of the drying tower under the carrying force of the adherence air curtain and are immediately evaporated and dried by hot flue gas, the annular main pipe of the hot air curtain and the venturi injection of the hot air curtain are annularly arranged in three layers to form the series connection relay of the adherence air curtain of the drying tower, the continuous and efficient operation of the adherence hot air curtain is kept, and the flue gas carrying a large amount of salt dust at the outlet of the hot air curtain drying tower enters the bag-type dust collector (23).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113860620A (en) * | 2021-11-15 | 2021-12-31 | 山西华仁通电力科技有限公司 | High-temperature bypass evaporation device for treating desulfurization wastewater |
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2020
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113860620A (en) * | 2021-11-15 | 2021-12-31 | 山西华仁通电力科技有限公司 | High-temperature bypass evaporation device for treating desulfurization wastewater |
| CN113860620B (en) * | 2021-11-15 | 2024-05-24 | 山西华仁通电力科技股份有限公司 | High-temperature bypass evaporation device for treating desulfurization wastewater |
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